DESCRIPTION (provided by investigator): Wood for cooking, and heating is an essential fuel to a large portion of world's population. Often cooking and space heating occurs on inefficient unvented stoves indoors exposing many to very high concentrations of wood smoke. The components of the smoke include hundreds of compounds created from incomplete combustion, many of which are toxic and even carcinogenic. Dioxins and furans, some of the most toxic substances in the world, are formed in wood combustion along with the other hundreds of compounds. The concentrations of dioxins emitted from a wood fire are lower than those from an industrial waste process when compared on a dioxin/furan per unit fuel mass basis. However an estimation of the actual quantity of dioxins/furans inhaled by a person in a kitchen cooking over an open fire is much higher. A rough estimation of the daily intake fraction of a woman, who cooks over an open fire yielded an intake that was in the range of international limits for dioxins and furans. We have been studying the impacts of indoor wood smoke from cooking for the past eight years in the rural highlands of Guatemala. This research has provided a wealth of information about the impacts of wood smoke and the success of an improved stove as an intervention. During the time spent in Guatemala we have noticed the practice of adding plastic to a fire as means of waste disposal as trash disposal is not available in such poor areas. The practice of burning trash is commonplace worldwide, especially in poor areas already burned with indoor biomass smoke. The addition of plastic may increase the concentrations of dioxins creating an even larger exposure to extremely toxic compounds. In order to better estimate the order of magnitude of the risk from dioxin exposure due to wood and plastic smoke we will quantify the concentrations of dioxins. We will first conduct a series of lab based chamber experiments to perfect a field sampling technique, as well as the chemical analysis. Then we will measure dioxin concentrations in a typical Guatemalan village kitchen from both wood and plastic combustion at varying ratios. Using this data and surveys on plastic burning along with kitchen particulate matter concentrations, and personal exposures to indoor air pollution collected from our two previous research studies in the same area, we will estimate dioxin exposure from wood smoke and the possibly increased concentrations from plastic burning. This study will provide a more accurate estimate of dioxin exposure from wood and plastic combustion, and possibly highlight an exposure to a large population of a extremely toxic pollutant. PUBLIC HEALTH RELEVANCE: Dioxins are considered to be one of the most dangerous chemical known to man. Quantifying exposures from wood and plastic smoke associated with indoor cooking may reveal a large previously unmeasured exposure to people already burdened with the severity of poverty.